London , England -LRB- CNN -RRB- -- Britain 's Prince William and fiancee Kate Middleton made their first official engagement as a couple Thursday , launching a lifeboat in Wales .

The pair , who are due to marry in April , officially named the `` Hereford Endeavour '' lifeboat in a ceremony at the Trearddur Bay Lifeboat Station in Anglesey , North Wales . Middleton , wearing a Vivien Sheriff black-feathered beret , three-quarter length cream coat and suede boots , poured a bottle of champagne over the lifeboat after Prince William made a speech commending the efforts of the volunteers and rescue crew .

`` We effectively have two launches today , '' said CNN royal contributor Mark Saunders . `` The launch of the lifeboat by William and Catherine and , at the same time , the launch of William and Catherine into this celebrity saturated world they are going to be living in . ''

Despite the modest nature of the event , hundreds of people turned out to watch the royal couple conduct their first official duty together .

`` In 20 years of royal reporting I 've never witnessed quite such excitement for such a single job , '' said Saunders .

One onlooker told CNN : `` It 's lovely ... I would have thought more people would have brought flowers and things for them but it 's lovely ... It 's low key which is what he -LRB- Prince William -RRB- wanted . ''

It 's the first public appearance the couple has made since they announced their engagement last November .

`` It 's a very low-key event , launching a lifeboat on the island where they both live ... it 's a very good debut event for them , '' said Saunders .

`` They have a very good relationship with the locals here , they are often seen at the local supermarket and buying wine from the local off-license . So for a first event , they could n't have picked a better one . ''

The reason for such a low-key ceremony , says Saunders , is to prepare Middleton for life as a royal .

'' -LRB- The royal family -RRB- have learnt many lessons from when Princess Diana first joined the royal family .

`` Diana was just thrown in the deep end and absolutely given no guidance whatsoever . They 're making sure this time round Catherine is well prepared , '' he said .

After naming the new Atlantic 85 lifeboat , Prince William and Middleton met members of the charity 's lifeboat crew along with fundraising volunteers and were given a demonstration of the vessel 's capabilities .

In a statement issued before the ceremony , Lifeboat 's Operations Manager , Aubrey Diggle said : `` It 's an honor to have Prince William and Miss Middleton at our naming ceremony .

`` Naming a new lifeboat is always a special occasion for the charity where we can thank our supporters and fundraisers . Having the royal couple there will make the day even more memorable for the whole community . ''

The couple currently reside in Anglesey while Prince William serves as an RAF search and rescue helicopter pilot .

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Prince William and Kate have conducted their first official engagement together

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The couple attended a lifeboat naming ceremony in Anglesey , north Wales

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The pair currently live in Anglesey while Prince William serves as an RAF pilot